Plaster-cast cutter



Feb. 14, 1939. E. RICHARDS 2,146,916

PLASTER CAST CUTTER Filed March 22, 1937 Patented Feb. 14, 1939Application March 22,

Claims.

The present invention relates to a device for aiding in the removal ofplaster casts, as applied to surgical operations.

The principal object of the invention is to pro- 5 vide a practical andeconomical means whereby the plaster cast encasing a limb or othermember of the body may be readily out without injury to the person.

The mechanical devices now generally used are of the electricallyoperated rotating saw type, or manually operated shears. The saw type inthe first place is relatively high priced and in the second place it isdifiicult to keep the saw free from clogging particularly caused by thebandage beneath the cast and also if the cast becomes softened byleakage from the wound or other moisture, the saw will become gummed anddifficult to operate. In using the shear type the casts are usuallyremoved in small sections, which in most cases is very discomforting tothe patient and in some instances injurious. The result is, the averagesurgeon will resort to the use of the ordinary straight knife, which ifnot used by an expert is very dangerous for slotting the cast, afterwhich the cast can be broken off. It is the aim of the present device toprovide a more eflicient means whereby the cast can be slotted prior toits removal without injury or cutting the patient.

With the above and other novel objects in view as will be hereinafterapparent the several novel features of the invention in its preferredform will be more fully described in the accompanying drawing in which:

Fig. l is a side elevational view of the invention, showing the knife incutting position and in dotted lines in a lifted position.

Fig. 2 is a top plan view, with the knife and the knife assemblyremoved.

Fig. 3a is a side and Fig. 3 an end view of the bracket member 2.

Fig. 4 is a side and top View of the knife, or blade carrying handle 3.

Fig. 5a is a side and Fig. 5 an end view of the 5 knife or blade 4.

Fig. 6 is a sectional view taken along the line A-A of Fig. l.

The invention therefore consists of upper and lower plate members 8 andii] running substantially parallel to each other. These members aresecured at one end to a relatively narrow perpendicular member I2, theother end being open for admitting the cast. Secured to the device andadjacent the closed end is a handle [4 for 1937, Serial No. 132,390

ETED STATES PATENT OFFICE.

member 8 is adapted to receive a slidable bracket 2 upon which ismounted the knife carrying handle 3. The upper member 8 is alsopreferably provided with a centrally located longitudinal slottedopening l6 extending from a point near the handle i i to a point nearthe opposite or open end, for allowing the operation of the knifetherethrough, as shown best in Figs. 1 and 2. The lower member H3 isprovided with a groove l8, which extends partly through the lower platefor receiving the point of the knife 4, the bottom portion of the groovepreventing the knife from extending beyond the lower member.

The knife 4 is mounted upon the knife carrying handle 3 by suitablescrews 20 and the knife carrying handle is in turn mounted upon thebracket 2 by the screws 22, thus making up the knife assembly. Thebracket 2 is adapted to slide easily over, and along the upper member 8.The lower end portions 24 and 25 of the bracket 2 are bent inwardly toslide along the under surface of the upper member to prevent the bracketfrom raising upwardly off the member 8 when pressure is applied to thehandle 3 when the knife point is in contact with the upper surface ofthe lower member I II.

The bracket has extending upwardly therefrom a bifurcated portion 28 anda hole 39 extending therethrough for receiving the screw 22 upon whichthe knife carrying handle is pivoted.

The knife carrying handle 3 is bent to form two portions 3 and 3". Theportion 3" when carrying the knife is shown inclined about 50 degrees,(see Fig. 1) but the cutting angle of the knife may be varied somewhatwithout departing from the spirit of the invention.

The obtuse angle formed by the two bent portions is positioned towardthe rear, or supporting handle l4. Therefore the portion 3 of the knifecarrying handle extends upwardly nearer a perpendicular line'to themembers 8 and I0 than does the portion 3".

This is to afford a better position in grippingthe handle when thedevice is being operated.

minimum loss of time.

In operation the device is held in one hand by the supporting handle l4and the lower member I0 is inserted under the cast C while the otherhand operates the knife.

While the member [0;

is being inserted the knife is withdrawn to a position similar to thatshown by the dotted lines in Fig. 1. The assembly is then moved forwarduntil the knife comes in contact with the outer end l6 of the slot I6.The handle 3 is then moved upward until the lower point of the knifecuts through the cast and in contact with the bottom of the groove I 8.The knife is then drawn rearwardly toward the member l2, pressingupwardly on the knife handle as it is moved along the member 8, toinsure that the point of the knife is within the groove. If the cast islonger than the first out, which is usually the case, the device ismoved forward. The narrow member I2 is moved within the cut made in thecast by the knife and the operation is repeated until the entire casthas been cut, after which it can be broken off with comparative ease. Itis to be understood that the hand operated knife may be replaced with apower knife if desirable.

It is obvious the device is simple in construction and economical in itsoperation. The principal parts may be cast from some suitable material,such as an alloy of aluminum for lightness and strength and thenpolished and machined. Or it may be made in any other manner that ismore suitable to its manufacture. Because of the hardness and characterof the plaster casts the knife should be made of a very hard steel andwell sharpened, or material that will not easily dull. Its operation issuch that it not only simplifies the surgeons task, but the averagenurse or orderly can be entrusted to use it in confidence of not cuttingor injuring the patient should the occasion arise for them to performthis duty.

While I have shown and described a preferred form of my invention itwill be understood that I have done so merely for clarification and thatmy invention is best defined in the following claims.

I claim:

1. A portable cutting tool for cutting plaster casts having upper andlower relatively narrow plate members extending substantially parallelto each other, one end of said members being open, means at the otherend for rigidly supporting said members apart in said relationship, aknife assembly slidable longitudinally upon the upper member, the saidknife adapted to contact the said lower member as the said knifeassembly is moved along the upper member.

2. A portable cutting tool for cutting plaster casts having upper andlower relatively narrow plate members extending substantially parallelto each other one end of said members being open, means at the other endfor rigidly supporting said members apart in said relationship, a, knifeassembly slidable longitudinally upon the upper member, the said knifeadapted to contact the said lower member as the said knife assembly ismoved along the upper member, handle means associated with the saidparallel members adjacent the supporting end for manually supportingsaid cutting tool.

3. A portable cutting tool for cutting plaster casts having upper andlower relatively narrow plate members extending substantially parallelto each other, means at one end for rigidly supporting said membersapart in said relationship, the opposite end of said plate members beingopen, a knife assembly slidable longitudinally upon the upper member,means for operating the said knife assembly, means for limiting themovement of said knife assembly along said upper plate, the movement ofsaid knife assembly being such that the lower end portion of the knifewill not move beyond the open end of the lower plate and meansassociated with the said parallel members for manually supporting saidcutting tool.

' 4. A portable cutting tool for cutting plaster casts having upper andlower relatively narrow plate members extending substantially parallelto each other, one end of said members being open, means at the otherend for rigidly supporting said members apart in said relationship, aknife, guiding means associated with the upper plate member for slidablyguiding the knife longitudinally along said upper member, the said knifeadapted to contact the said lower member as the knife is moved along theupper member.

5. A portable cutting tool for cutting plaster casts having upper andlower relatively narrow plate members extending substantially parallelto each other, one end of said members being open, means at the otherend for rigidly supporting said members apart in said relationship, aknife, guiding means for guiding said knife longitudinally along saidupper member, the said knife adapted to extend between the said membersand contact the said lower member as it is moved along the upper member.

ESTELLE RICHARDS.

